In order to convey heavy oils or bitumen from oil sand or oil shale deposits using pipe systems that are inserted through bore holes, the flowability of said heavy oils or bitumen must be considerably increased. This may be achieved by increasing the temperature of the deposit, referred to hereinafter as a reservoir. If, for this purpose, the known SAGD method is used exclusively, or inductive heating is used either exclusively or in addition to assist the known SAGD method, there is the problem that the inductive voltage drop along the long length of the inductor of, for example, 1000 m, may lead to very high voltages of up to several hundred kV, the reactive power of which cannot be controlled either in the insulation against the reservoir or the earth, or at the generator.
In order to assist reservoir heating by steam injection in accordance with the known SAGD method (steam assisted gravity drainage) or else as a complete replacement of this steam injection, different electromagnetically active inductor and electrode configurations may be used that are disclosed in detail in the applicant's unpublished applications DE 10 2007 036 832, DE 10 2007 008 292 and DE 10 2007 040 606.
In the general prior art of induction heating, the formation of highly inductive voltages can be prevented by a series connection consisting of inductor portions and integrated capacitors that are to be adapted to the working frequency as a series resonant circuit. The applicant's unpublished application DE 10 2007 040 605 discloses, in detail, a coaxial conductor apparatus comprising concentrated capacitances and implementing the principle of distributed capacitances based on the published German patent application DE 10 2004 009 896 A1. The former conductor apparatus has different characteristics, such as low flexibility, high production costs and expensive high-voltage ceramics. The latter conductor apparatus is not suitable for the intended purpose mentioned at the outset.